Measurement and control of mooney viscosity in the polymerization of conjugated dienes



H. B. lRVlN June 14, 1966 MEASUREMENT AND CONTROL OF MOONEY VISCOSITY IN THE POLYMERIZATION OF CONJUGATED DIENES 5 Sheets-Sheet l Filed May 18, 1961 im A? H. B. 1Rv1N MEASUREMENT AND CONTROL OF MOONEY VISCOSITY IN THE POLYMERIZATION OF CONJUGATED DIENES Filed May 18, 1961 5 Sheets-Sheet 2 MOONEY RECORDER CONTROLLER 2 r. F |119 11 N m f c um R NP mA |11|. M 1L n S u 1\ o n N n 4 1 f 6 B VIIJMI 11| m L m l L C .l 2 1|l I TIBA INVENTOR H. B. |RV N POLYMER |09/ 8 7. m lr.- f W NY U E O H RN 3 TS EO UO Il MZ ,1 LC l Y OS 6 Lm Sl 2 OE V 1 Pw O n n M Tm J1 l 2 (Il A n \|||l- J R M R RE lf, M 2 MEM mE 3 NU IIIIII IIIGT OM OCT Lw.. Mo Mmm C C n 3 7 B m H BSL O A P w( Ml e um 9 OL PO S L A 7' TORNE K$` H. B. lRVlN June 14, 1966 MEASUREMENT AND CONTROL OF MOONEY VISCOSITY IN THE POLYMERIZATION OF CONJUGATED DIENES 3 Sheets-Sheet 5 Filed May 18, 1961 United States Patent O 3,256,262 MEASUREMENT AND CONTROL OF MOONEY VlSCOSlTY IN THE POLYMERIZATION F CON- .FUGATED BIENES Howard B. Irvin, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Filed May 18, 1961, Ser. No. 111,110 17 Claims. (Cl. Zoll-94.3)

This invention relates to the measurement of Mooney viscosity of polymers of conjugated dienes. In one aspect, the invention relates to a method for controlling Mooney viscosity in the polymerization of conjugated dienes.

Numerous methods are described in the literature for polymerizing conjugated dienes, such as l,3butadiene, including emulsion polymerization, alkali metal-catalyzed polymerization, and alim-catalyzed polymerization. It has recently been discovered that a polybutadiene containing at least 95 percent cisdA-addition can he produced by polymerizing 1,3-butadiene with an initiator comprising an organometal, e.g. a trialkyl aluminum, and a titanium halide, such as titanium tetraiodide, a mixture of titanium tetrachloride and titanium tetraiodide, or a mixture of titanium tetrachloride and iodine. One suitable lmethod for polymerizing conjugated dienes is disclosed in the copending U.S. patent application, Serial No. 578,166, filed April 16, 1956, by R. P. Zelinski and D. R. Smith, now U.S. Pat. 3,178,402.

In the production of cis-1,4-polylbutadiene and other conjugated diene polymers in the presence of an initiator system comprising an organometal and a titanium halide, it has been found desirable and sometimes dii'licult to control the Mooney viscosity of the final product. One reason for 4the variation in the final M-ooney is .the variation in poison level in streams fed to the reactors. This change in poison level aiects the activity of the initiator for the production of the polymer as well as such properties as molecular weight, Mooney viscosity, inherent viscosity, conversion rate, etc. By conventional practices the effluent from the reaction zone is passed through a series of ash tanks wherein unreacted conjugated diene and a portion of the solvent are removed from the poly- -mer solution. A portion of the lbottoms from these ilash tanks is `then removed and sent to a laboratory for analysis of Mooney viscosity. This is a time-consuming operation resulting in a considerable delay between the time that the reaction conditions have changed and the .time that proper remedial action can be taken based on the laboratory analysis.

It is an object of this invention to provide a novel process for the determination of Mooney viscosity of a rubbery polymer of a conjugated diene.

It is another object of this invention to provide a novel process for :controlling ythe Mooney viscosity of a polymer of a conjugated diene.

Still another object of this invention is to provide a novel process for measuring the Mooney viscosity of a polymer of a conjugated diene and controlling the polymerization of the conjugated diene so as to produce a substantially constant Mooney viscosity.

Yet another object of this invention is to provide a novel process for blending polymers of conjugated dienes so as to produce a substantially constant Mooney viscosity.

3,256,262 Patented June 14, 1966 ice proved apparatus for the measurement of .Mooney vis-v cosity of a polymer of a conjugated diene.

A further object of the invention is to provide an improved process and apparat-us for the measurement of Mooney viscosity of a polybutadiene having a high cis- 1,4-content, such as from to 98 percent and hi-gher.

Other and further objects and advantages of theinvention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.

These and other objects of the invention are broadly accomplished in a process comprising .contacting a conjugated diene in a reaction zone in the presence of an initiator and a diluent and recovering an effluent comprising a polymer solution from said reaction zone by the improvement comprising measuring the weight percent solids and the solution viscosity of said euent and determining the Mooney viscosity from said measurements.

In one aspect of lthe invention, the thus determined Mooney viscosity is used to adjust at .least one process variable so as to maintain a substantially constant Mooney viscosity for .the polymer product.

In another aspect of the invention, the thus determined Mooney viscosity is used to divert from the effluent stream tha-t portion of the stream having a Mooney viscosity outside a predetermined range of Mooney viscosity.

lIn still another aspect of the invention, the aforesaid diverted effluent stream is blended with the polymer prod-uct stream in a ratio suicient to adjust the Mooney viscosity of said stream to Within a predetermined range.

Preferably the monomeric material polymerized lto produce robbery polymers comprises a conjugated diene contaning from 4 to `8, inclusive, carbon atoms per molecule. Examples of conjugated dienes which can be used include 1,3-tbutadiene, Z-methyl-labutadiene (isoprene), 2,3-dimethyl 1,3 butadiene, .Z-met-hyl-l,S-pentadiene, chloroprene, 2,3-dimethyl 1,3 pentadiene, 2-methyl-3- ethyl-1,3-pentadiene, yZ-methoxybutadiene, 2-phenylbutadiene, and the like. v

This invention is applicable to the polymerization of the albove-deiined conjuga-ted dienes either alone or in admixture 'with each other and/ or with, in minor amounts, one or more other compounds containing an active CHFC -group which are copolymerizable therewith. Included among these latter compounds are aliphatic 1- olens having up to and including 8 Icarbon atoms per molecule, such as ethylene, propylene, l-butene, l-hexene, and l-octene. Branched chain olerns, such as isorbutylene, can be used as well as 1,1-dialkyl-substituted and 1,2- dialkyl-substituted ethylenes such as butene-Z, pentene-2, hexene-2, heptene-2, .Z-methylbutene-l, Z-methylhexene-l, Z-ethylheptene-l, and the like. Other olens which can be used include diand polyolens, such as 1,5-hexadiene, 1,4-pentadiene and 1,4;7-octatriene, and cyclic olcfins, such as cyclohexene. Other examples of compounds containing an active CH2=C ygroup which are copolymeri zable with one or more of the conjugated dienes are styrene, divinyl benzene, 3-vinyl toluene, l-vinyl naph- .thalene, 3-methyl styrene, acrylonitrile, methacrylonitrile, methyl arcrylate, methyl methacrylate, vinyl acetate, vinyl chloride, Z-met-hyl-S-Vinylpyridine, 2-vinylpyridine, 4-vinylpyrid-ine, and the like.

The invention is particularly applicable to a process for the polymerization of 1,3-butadiene with an initiator comprising (a) an organometal compound having the structural formula RUM wherein R is a member selected `from the group consisting of alkyl, cycloalkyl, aryl, aralkyl, and alkaryl radicals containing from 1 to 20 carbon atoms, M is a metal selected from the group consisting of aluminum, galliurn, indium, zinc, cadmium, beryllium and V mercury and n is the valence of the metal and (ib) a memiber selected from the group consisting of (l) titanium tetraiodide, and when M is aluminum, (2) titanium tetrachloride and titanium tetraiodide, and (3) iodine and a titanium halide having the formula TiX4 where X is selected from the group consisting of chlorine and bromine.

application of Naylor and Hooten, Serial No. 754,175,

led August 11, 1958, now U.S. Pat. 3,205,212.

The polymerization process of this invention is usually carried out in the presence of a diluent. Diluents suitable for use in the process are hydrocarbons which are substantially inert and nondetrimental to the polymerization reaction and include aromatics, such as benzene, toluene, xylene, ethylbenzene and mixtures thereof; straight and branched chain parains which contain up to and including 12 carbon atoms per molecule including normal pentane, isopentane, normal hexane, isohexane, 2,2,4-trimethylpentane (isooctane), normal decane, mixtures of these paraflinic hydrocarbons and the like; aromatic halides such as chloronaphthalene and the like; and cycloparaffins, such as cyclohexane and'methylcyclohexane. Furthermore, mixtures of any of the aforementioned compounds can be used as diluents. lt is usually preferredto carry out the polymerization in the presence of an aromatic hydrocarbon since polymers having the higher cis contents a-re produced when operating in this manner.

The polymerization process can be carried out at temperatures varying over a rather wide range such as from -100 to 250 F. The selection of the proper temperature and pressure depends upon the particular diluent and initiator selected. The polymerization reaction is generally carried out under autogenous pressure or at any suitable pressure, preferably suicient to maintain the reaction mixture substantially in the liquid phase. It `is to be understood also that it is generally necessary to conduct the polymerization in the uid state in order to most effectively utilize the method of this invention so that adequate mixing can readily occur.

It will be readily understood by those skilled in the art that the particular mole ratio of titanium halide to organometal depends on the organometal used. However, within any given initiator system it is necessary that the ratio be maintained within that ratio range peculiar to that initiator system in order to initiate and sustain the reaction. Generally, the mole ratio of metal/Ti at the time of initiation of the reaction is in the range of 1.511 to 15 :1- while the ratio can be in the range of O.75:1 to 2:1 at termination. For Al/Ti the ratio is generally in the range of 15:1 to 2:1 during polymerization although the initial ratio is sometimes higher, It is to be further understood that not all portions of the above ranges are operable for all organometals.

As discussed hereinbefore, the Mooney viscosity of polymer discharged as bottoms from the flash tank may vary depending on several factors such as the poison level in feed streams to the reactors. I have discovered that the measurement of solution viscosity and weight percent polymer of the polymer solution yields information which can be utilized to compute Mooney viscosity of the polymer, thereby making it possible to more effectivelyand quickly control the reaction.

Solution viscosity and weight percent polymer are readily and rapidly determinable by many methods known to those skilled in the art. For instance, one method of determining solution viscosity is the withdrawal *of a sidestream of the polymer solution and pumping said polymer solution at a constant rate through a uniform circular tube in a constant temperature bath. The pressure drop is proportional to the solution viscosity. Commercial viscosmeters produced for sale by various instrument companies may also be utilized for the measurement of solution Viscosity. Acceptable viscosimeters are (l) Continuous Indicating and Recording Viscosimeter Model No. 1,077 or Model No. 1251B produced by the Hallikainen Instrument Company, and (2) Continuous Polymer Viscosimeter Model No. 1218 produced by the Norcross Instrument Company.

The amount of polymer present in the polymer solu- `tion in terms of weight percent is determinable from a number of related properties, such as refractive index, infrared absorption, ultraviolet absorption, chromatographic absorption and the like. Particular-ly suitable for in-line determinations is a high temperature differential refractometer such as produced by Consolidated Electrodynamics Corporation, Pasadena, California, and described in Bulletin No. 1839.

The Mooney viscosity of polymer recovery from solutions is conventionally determined by ASTM Method D 927-57T.

Although the particular relationship of solution viscosity, weight percent solids in solution, and Mooney viscosity of the polymer depends on the particular polymer, temperature and shear rate, the following equation has been found satisfactory for correlating the Mooney viscosity of a cis-1,4-polybutadiene solution in a concentration of 1 to 20 weight percent with the solution viscosity being measured at F. and at a shear rate of 10() sec.

1.484-0.9798(RI) where ML is Mooney viscosity, RI is refractive index, and ,u. is solution viscosity in poise.

The determination of the above or similar equations or the adaptation of same to t particular requirements is well within the skill of the art. From this relation a simple calculation will result in a determination of Mooney viscosity much more rapidly than by heretofore used methods. In addition, analog or digital electronic computers are readily available which will receive a continuous or pulse type signal representative of the solution viscosity and ano-ther signal representative of the refractive index and produce a third signal representative 0f the Mooney viscosity. Suitable analog computers include Model TR-lO, Electronic Associates, Inc., Long Branch, New Jersey, and Model CM-3, Southwestern Industrial Electronics Corp., Houston, Texas.

This Mooney viscosity determination may be used to control a process variable so as to produce a polymer having a substantially uniform Mooney viscosity. One important process variable is the concentration of initiator within the reactor. A preferred method of controlling the concentration is by adjusting the rate of introduction of initiator into the reactor although it is also within the scope of the invention to vary the ratio of initiator cornponents. A change in the concentration of initiator has several effects, including an effect on Mooney viscosity. For example, when polymerizing 1,3-butadiene in the presence of iodine, titanium tetrachloride and triisobutylaluminum at a constant ratio of initiator components, a decrease in initiator concentration can result in, an increase in conversion rate, inherent viscosity, Mooney viscosity and molecular weight. At a given ratio of iodine to titanium tetrachloride, increasing the amount of TIBA produces slightly higher cis contents, lower molecular weights, lower inherent viscosity and lower Mooney values. Further, at a given ratio of TIBA to titanium tetrachloride, increasing the amount of iodine increases the yield and molecular weight, increases the reaction rate and increases the Mooney viscosity. However, it should be noted that for some systems there may be limitations to the range within which the catalyst component ratios may be adjusted without affecting yield or cis-4 content.

Another process variable which is controllable by Mooney viscosity relationships is the blending of polymers which are outside of predetermined limits. These aspects of the invention will be discussed hereinafter in relation to the drawings, particularly FIGURES 3 and 4.

FIGURE 1 represents a general flow sheet for the production of cis-1,4-polybutadiene and further describes the method of this invention for determining Mooney viscosity.

FIGURE 2 is a diagrammatic representation of a method of controlling catalyst input by one aspect of this invention.

FIGURE 3 illustrates the feature of diverting polymer from the main product stream.

FIGURE 4 illustrates the feature of blending polymers of different Mooney viscosities into the main product stream.

To more fully describe my invention reference is now made to the drawings. In discussing the process in con- -nection with the drawings reference is made to specific materials and reaction conditions for purposes of simplicity. It should be understood, however, that my invention is not limited in this fashion.

In FIGURE l butadiene is continuously fed by pump through line 11 to mixing zone 12, such as a multiorifice contactor. Reaction diluent, toluene, is continuously fed into line 11 through line 13 and likewise a recycle stream containing toluene and butadiene is fed to line 11 through line 14. Thus the recycle materials and the fresh butadiene and reaction diluent are thoroughly mixed in contactor 12. This mixture is then passed through line 16 to heat exchanger 17 wherein the mixture is cooled, preferably to about 5 to 25 F. Initiator is then added to the cooled mixture of monomer and diluent in line 18 through lines 15 and 19. Iodine is added through conduit 20 and a titanium tetrachloride through line 21, while a solution of triisobutylaluminm is added through line 15. The butadiene is contacted with the initiator under polymerization conditions in line 18. The reacting mixture passes through line 18 to reactor 22.

The etiuent from reactor 22 passes through line 23 to reactor 24 and the efuent from reactor 24 likewise passes through line 26 to a downstream reactor in series, nally entering the last reactor 27 in the series. Any number of reactors can be employed in this series; preferably at least 3 reactors and generally not more than 12 to 15 are used. The pressure of the reaction is maintained so that the reaction mixture is in a liquid phase. The preferred operating temperature is in the range of 10 to 100 F. and I prefer to operate the reactors in series so that the temperature of the first reactor is less than the temperature of the final reactor. The temperature of the intermediate reactor can be at values intermediate the first and final reactor of the series. I have found that this is desirable in order to keep the temperature of any reactor from going above a desired maximum. Since the concentration of monomer is highest in the first reactor, there is a tendency for a more rapid reaction therein and by maintaining the temperature of the first reactor at a lower value than in the subsequent reactors it is much easier to mainincrementally to the reaction by passing a portion of the butadiene from line 11 through line 28 and introducing this portion to the downstream reactions via lines 29 and/ or 30 and so forth. By varying the amount of monomer added in this fashion it is also possible to control the viscosity or Mooney of the polymer in the finished product; for example, by adding a portion ofthe monomer to the downstream reactors I can increase the Mooney value of the final polymer. The Mooney value can also be decreased or increased by increasing or decreasing, respectively, the amount of initiator fed to the reactor.

As the reaction effluent leaves the last reactor 27 in the series and passes through line 31 a nonvolatile initiator inactivating agent having active hydrogen groups is added through line 32 in an amount suicient to inactivate the initiator. The reaction efliuent and the inactivating agent are thoroughly mixed in mixer 33. By nonvolatile I refer to the relative Volatility of the agent under the con- A ditions employed to separate unreacted material from the reactor eiiiuent. Since these recovered materials are to be recycled to the reaction it is important that essentially all of the initiator inactivating agent remain with the polymer and initiator. It is only through the use of such relatively nonvolatile agents that I can stop the reaction by adding excess initiator poisoning immediately following the reactors and prevent recycling initiator inactivator to the reactor feed via stream 14. A carefully metered amount of water can be used under certain conditions. Examples of suitable nonvolatile initiator inactivating agents are rosin acid, hydroquinone, pyrogallol, catechol, guaiacol, benzoquinone, tetraphenylhydrazine, aniline, quinoline, nitrobenzene, benzyl mercaptan and the like. In general, materials can be used from such classes as fatty acids, e.g. stearic acid, glycols, e.g. glycerol monoesters, alkyl gallates, xanthogen polysulfides, N-substituted dithiocarbamates, glycerol, alkyl polysuldes, furfural, and the like. It should be appreciated that the above list is not exhaustive but is given to provide a better understanding of what is meant by my generic description.

For a further and more complete description of the addition of the rosin acid, reference is hereby made to the copending application of Robert F. Dye, Serial No. 45,- 042, filed July 25, 1960, now U.S. Pat. 3,099,648.

As the efuent stream leaves mixer 33 through line '34, antioxidant is added via line 36 and the stream again passes through a mixer 37 and thence through line 38 to surge tank 39. Any of a number of well known rubber antioxidants can be used, for example, N-isopropyl- N'-phenyl-p-phenylenediamine, N-phenyl-Ncyclohexyl p-phenylenediamine, and the like. One or more surge tanks can be employed and all of these tanks should be blanketed with an inert gas such as nitrogen. The pressure within these tanks is maintained by pressurizing the tank with nitrogen by opening valve 40 in line 41 or the pressure can be reduced lby venting the vapors in tank 39 to a flare by opening valve 42 in line 43. This pressure control can, of course, be done automatically. v

The effluent stream in which the initiator has been inactivated passes from surge tank through line 44, pump 46 and heater 47 to ash tank 48. The pressure of the stream is increased substantially lby pump 46, heated in exchanger 47 and then reduced to about atmospheric pressure or slightly above in flash vessel 48. Flashed vapors are withdrawn overhead from vessel 48 through conduit 49 while the unvolatilized liquid is withdrawn through conduit 50. This ashing operation is then repeated by repressurizing the liquid in conduit 50 in pump v51 and heating in exchanger 52. The pressure is again let down in flash vessel 53, flashing vapors which pass overhead through conduit S4. This operation is performed again with the liquid in conduit 56 utilizing pump 57 and exchanger 58, the third flash occurring in vessel 59. Vapors from vessel 59 pass overhead in conduit 60 and all the flashed vapors are gathered in header 61.

Pumps 46, 51 and 57 can be operated so that the pressures developed decrease sequentially.

The overhead vapors from ash vessels 48, 53 and 59 pass through line 61 to air cooled condenser 62 and thence to cooler 63. The condensed liquid which contains butadiene and a substantial .amount of toluene is passed through line 64 to condensate receiver 66. The pressure in receiver 66 is maintained in the same f-ashion as discussed in connection with storage tank 39 utilizing a blanket of nitrogen which enters through line 67. Vapors can be vented through line 68. The condensate iswithdrawn from receiver 66 through line 69 and passed by pump 70 through line 71. Most of this condensate is recycled through lline 14 to the polymerization process as previously described. A portion of the condensate is purged through line 72 to a purification operation in order to keep volatile impurities from building up in the system. The efuent stream is withdrawn from the last ash vessel 59 in the series Iand is passed via line 73 to subsequent recovery operations. At this point substantially all of the unreacted butadiene has been removed and the concentration of the polymer in the solvent has increased materially, for example, for about to 15 weight percent.

While not shown in the drawings, this polymer solution in line 73 can be passed to a storage tank and the polymer then recovered from the solution by steam stripping to remove the solvent. A slurry of polymer crumb in water is passed to a storage tank and the polymer is separated from the slurry by passing over a shaker screen, through a compacting auger and tinally through an extruder-drier. v

A portion of the polymer solution in conduit 73 is removed through conduit 77 and passed to the refractive index measuring zone 79 through conduit 78 and the.

solution Visco-sity measuring zone 83 through conduit 82. After the measurements of refractive index and the solution viscosity have been made the polymer solution is returned to the product stream 73 via conduits 80, 84 :and 81. In the preferred method of operation the instruments for determining refractive index and the solution viscosity produce a signal proportional to these determinations which is transmitted to a computer'86 which is built from commercial computer building blocks. Mooney computer 86 receives these signals and translates them into a signal proportional to the Mooney viscosity. A satisfactory equation for determining this Mooney from these measurements has Ibeen hereinbefore discussed. The signal produced by computer 86 is then transmitted to a Mooney recorder controller 87 which translates the signal into useful information.

v As shown in FIGURE 2, controller 87 is used to control the introduction of initiator into the reactor 22 through conduit 18. In this aspect of this invention, not only is the total amount of initiator entering the reactor maintained substantially constant but the ratio of initiator to monomer is also maintained constant while simultaneously maintaining the ratio of the individual initiator components substantially constant. A flow sensing device 74 disposed in the butadiene inlet conduit transmits a signal to flow rate ratio controller 76 proportional to the flow rate of the butadiene being introduced into the reaction zone. When the Mooney viscosity changes as determined by the methods hereinbefore described Mooney recorder controller 87 transmits ya signal which manipulates the set point of FRRC 76. Since it is important that the r-atio of initiator components and he ratio of total initiator to diolen be maintained substantially constant it is necessary that some vcontrol be maintained over these variables. This may be done manually or by 4any suitable instrumentative device known to those skilled in the art. By the instrumentative devices illustrated `in FIGURE 2 the ratios of initiator components and butadiene are controlled by three separate How rate ratio controllers. The ratio of titanium tetrachloride to butadiene is maintained at a substantially constant preset value by FRRC 7.6 which receives signals Lfrom flow sensing devices 74 and 136 and lactuates motor valve 137 disposed in conduit 21 so .as to regulate the flow of v titanium tetrachloride proportional to the ow of butadiene. The ow of iodine and triisobutyl aluminum are similarly maintained and kept in a fixed ratio to the butadiene ow and to each other. v FRRC 139 receives signals from FRRC 76 and ow sensing device 138 proportional to the flow of butadiene and iodine, respectively, and actuates motor valve 14111 so as to maintain a substantially constant flow ratio of iodine to butadiene. FRRC 142 receives signals Vfrom FRRC 76 and ow sensing device 141 disposed in conduit 15 so as to permit the actuation of motor valve 143 disposed in conduit 15 thereby maintaining flow rates of TIBA and butadiene at a substantially constant ratio. If the Mooney viscosity changes, the signal from controller 87 manipulates the set point of FRRC 76 which in turn manipulates the manually set point of FFRC 139 and 142.

FIGURE 3 illustrates the aspect of the invention wherein the portion of the polymer solution passing through conduit 73 which is outside the desired Mooney viscosity range is diverted from said conduit 73 for subsequent blending or disposal based on a determination of the Mooney viscosity by the method of this invention. The reference numerals in FIGURE 3 for those items which are in common With the previous figures are identical and further discussion of their function will be limited to their application in this aspect of the invention. Polymer solution which is within the predetermined desired range passes through conduits 73, 89, valve 90, conduit 91, mixing zone 92, which may be a surge tank containing an agitator or an in-line power driven mixer, and into conduit 93 for passage to the polymer recovery zone. Although valve is normally closed, it is opened either manually or by proper instrumentation when Mooney recorder'controller 87 indicates that the Mooney is within the predetermined desired range. In one convenient instrumentation system this signal from controller 87 is transmitted to a logic system 83 which will decide whether valves 90, 97, 101, 107 or 111 should be opened. This logic system may be any device suitable for making the decision as to which valve to open in response to a signal from controller 87. In its simplest form, the logic system -is a human being who makes a direct visual observation of the recorder stylus and opens the proper valve. However, more conveniently an instrument capable of making the decision is employed such as described in Process Instruments and Controls Handbook by D. M. Considine, pages 9-55 and pages 10-49 (1957). If the polymer is above specication, or predetermined desired limits, but within a range at which it may be subsequently blended, valve 97 is opened and valve 90 closed and the polymer isdiverted from conduit 89 into conduits 94, 96, through valve 97 and conduit 98 into a surge vessel 99. If the polymer is above the desired limit for blending, the valve 101 is opened instead and the polymer continues from conduit 94 through conduit 100, valve 101, conduit 102 and into surge vessel 103. A similar arrangement is used for polymer which is below specification. When the polymer is below specification but within blending range valve 107 is opened and polymer solution .passes from conduit 73 through conduits 1114, 106, valve 107, conduit 103 and mto surge vessel 109. If the polymer is below the limit desired for blending, valve 111 is opened instead and the polymer continues from conduit 11M through conduit 111B, valve 111, conduit 112 and into surge vessel 113. That portion of the polymer which has been collected in vessels 103 and 113 may be either discarded or subsequently used in various ways.

It is possible to blend polymers having diierent Mooney viscosities to attain a polymer having the desired Mooney viscosity since the relationship is a simple linear function of the Mooney viscosity. Therefore, it is possible for the high Mooney polymer contained in tank 99 to be blended with the low Mooney polymer in tank 109 to obtain polymer of the predetermined desired Mooney viscosity. To achieve this the average Mooney viscosities within tanks 99 and 109 are determined and the amount of each necessary to achieve the desired Mooney is calculated. Valves 116 and 119 are then opened to the desired position thereby permitting high Mooney polymer from vessel 99 to Awherein the determination of solution viscosity and refractive index of the polymer passing through the main product stream 91 is used to control the amount of the high Mooney polymer and/or low Mooney polymer being continuously introduced into mixing tank 9 2 so that when the polymer solution passing through conduit 91 is within the predetermined desired range but outside a narrower preferred desired range, the proper amount of high and/or low polymer will be introduced into mixing tank 92 to bring the polymer within the preferred range. As shown in FIGURE 4, the off-specification polymer has been diverted into tanks 99 and 109 as hereinbefore described for FIGURE 3. The reference numerals which are in common with those of hereinbefore described gures are identical. The main product stream passes through conduits 93, 121 and 122 to the polymer recovery zone (last shown). A portion of the product stream is diverted from conduit 93 into the refractive index measuring Zone 126 through conduits 123 and 124. A portion of this portion continues through conduit 129 to the solution viscosity measuring zone 130. These measurements are made as hereinbefore described in FIGURE l. Upon the completion of the measurements the portion passing through the refractive index measuring zone 126 continues through condiuts 127 and 128 and is combined with the portion from the solution viscosity measuring zone 130 from conduit 131 into the main product stream 122. As described hereinbefore with reference to FIG- URE 1, a signal proportional to the refractive index and a signal proportional tol the solution viscosity is transmitted to the Mooney computer 132 wherein a signal proportional to the Mooney viscosity, calculated as hereinbefore described for FIGURE 1, is transmitted to Mooney recorder controller 133 which not only records the Mooney viscosity visible but also passes this information to a logic system 134 Which has been heretofore supplied with information which permits it to decide whether to open.

valve 116 or valve 119. This logic system can be a person or an instrumentation system as hereinbefore described. For example, if the predetermined Mooney range for polymer passing through conduit 91 is 45 i 5 10 EXAMPLE r As an example of my invention the following specific operation is described in detail with reference to the flow 'as shown in the above-discussed drawing. In this example nine reactors are employed in series operating at the pressure and temperature shown in Table I. Polybutadiene is formed by contacting butadiene with an initiator which contains triisobutylaluminum in combination with titanium tetrachloride and iodine to a total conversion of 60 percent. The residence time in thenine reactors is 2.1 hours. The initiator is quenched after polymerization by the addition of rosin acid in an amount suicient to provide about 2 pounds per hundred of rosin acid in the recoveredpolymer. This is somewhat in excess of twice the amount necessary to fully quench the initiator. Methylene-2,2'bis[4-methyl-6-tert-butylphenol] is added as an antioxidant. The Yeiiluent in which the initiator has 'thus been inactivated is ashed in three zones in series, The Vaporized material is recycled in part and purged in part, and the unvaporized material is passed to subsequent operations for polymer recovery.

` TABLE I Incremental Vessel Tempera- Pressure Conversion ture F.) (p.s.i.a.) (percent) Reactor 2 (24) 31 65 10.3

Reactor 3 35 64 7. 5

Reactor 4 38 64 6. 5

Reactor 5 39 63 5. 3

Reactor 6 40 63 4. 2

Reactor 7..- 40 62 3.9

Reactor 8....- 40 61 3.6

Reactor 9 (27) 40 60 3.0 Storage (39) 40 Exit 'Heater (47) 340 Flash 1 (48) 227 Exit Heater (52) 340 Flash 2 (53) 235 Exit Heater 328 Frasi; 3 (59) 235 Receiver (66). 100

but the preferred range is 45 i 2 and the polymer passing through conduits 93 and 123 has a Mooney of 49 determined as hereinbefore described, logic system 134 transmits a. signal to valve 119 to permit the introduction into conduit 91 of polymer which is below the predetermined range so as to bring the polymer solution within the range of 45 i 2. When the Mooney reaches the preferred range as determined by the system hereinbefore described, valve 119 is closed. Since completely closing valves 119 or 116 may result invexcessive cycling, it is within the scope of the invention to keep either or both Of the valves partially open until the polymer in stream 91 returns to the desired Mooney range. It is also Within the scope of the invention to open valve 116 or 119 proportional to the variance in the Mooney viscosity, as determined by computer 1 32, from the desired level.

A portion of the polymer solution in conduit (73) is continuously Withdrawn and a determination made of its solution viscosity and Weight percent solids. From this data computer 86 determines the Mooney viscosity. A signal is then continuously transmitted to Mooney recorder controller 87. This controller is preset so as to manipulate the set point of FRRC 76 When the Mooney viscosity is outside the predetermined desired`range of 451-2. If, for various reasons, the Mooney of the polymer product increases as determined by computer 86, controller 87 then manipulates the set point of FRRC 76 so as to increase the amount of initiator being introduced into the reactors to a total of 1350#/SD until the Mooney decreases to within the desired range. These changes and vresults are tabulated in Table II.

D etermined on a high temperature differential refractometer descrlbed in Bulletin No. 1839, Consolidated Electrodynamics Corporation, Pasadena, California.

b Determined on a Model No. 1251B Viscosimcter, I-Iallikainen Instruments.

Calculated by the following equation:

L iogm Haas-526.8 (Rr) m34-0.9798 (RI) M'L=Mooneyviscosity RI Refractive index =Solution viscosity, poise The data used to develop this equation measured u at 150 F. and at a shear rate of sec-1.

Where 1 1 1 2 EXAMPLE II TABLE V To illustrate a second aspect of the invention shown in FIGURE 3 the Mooney of the polymer passing to the Conduit Conduit Conduit (91) (120) (93) polymer recovery zone 1s controlled by diverting all 5 olymer from stream 73 which does not fall Within the Idesired range of 45i5. The Mooney of the polymer in vlvstolotrieilii': n iii 14?? ig stream 73 is determined by computer 86 as in Example I llliglfliigblgr 1 u, Ogg ii's 17 Og and a signal transmitted to controller 87. Valves 90, 97, Mooney, arcor combining 1 4 43.1 46.9 101, 107, 1-1-1, 116 and 119 lare normally in a closed position. Controller 87 then transmits a signal to logic sysl0 iDotorinined from tho equation in Exnnipio I. tem 88 which then decides which valve to open based on the Mooney of the polymer in stream 73 as shown in Table While certain examples, structures, compositions and III. process steps have been described for purposes of illustra- TABLE III Valve Total Stream, (90) (97) (101) (107) (111) (116) (119) 1b./SD

Mooney:

20. open -39 99 open 9, 224 -50 open 927,707 50.01-90 open 7 90 open Total (93) 946, 64o

It will be seen that most of the polymer (approximately tion, this invention is not limited to these. Variation 98 percent) is acceptable and only la small portion needs `and modication within the scope of the disclosure and the to be diverted from the main stream. claims can readily be elected by those skilled in the art. EXAMPLE HI 35 .For example, insorne instances it is desirable to add the trialkylaluminum initiator component to the feed stream The Polymer solutions of Example Il Which haVe been in a predetermined .amount prior to introducing the other diVerted into Vessels 99 and 109 are Periodically blended initiator components. This is advantageous since the tritogether to Produce a Polymer haVing a Mooney of alkyl-aluminum acts .as a scavenger to remove initiator The vessels 99 and 109 contain agitators which provlde a 40 poisons from the .feed Stream thereby reducing the' tef. uniform blend of the Polymer solutions contained thereinfective amount of trialkylaluminum. Since the catalyst The amount of each batch necessary to "Produce a iinal level to the reactor is important, it is readily apparent that Mooney of 45 (a simPle linear relationship of Mooneys) lthe portion of catalyst used in scavenging must not only is determined and Values 11d and 119 are manually be replaced but must be metered into the system accurateoPened so as to Produce the desired flow rates from each 45 ly. One convenient Way of regulating the trialkylalumivessel andthe batches are remtrodud 1I1t0ti1e mam poly.- nnm iovei is by tho determination of tho iriaikyininniimer Stream 93 through mixing tank 92 num content in the inlet conduit to the reactor and then TABLE 1v adjusting the predetermined amount of this component Ave Mooney 99 47-3 ntrOdUCed into Said Conduit in response to said determina. AVe- Mooney 109 43l 50 tiOn. vFor even more stable control a system may be Total quantity 99, #/SD 9709 PrOVdSd in Which the trialkyllaluminum level controlled Total quantity 109 #/SD 9224 Aby the trialkylalurninum measuring-controlling moans is Blend 117, /SD 8400 adjusted by the output signal from the Mooney omputorn Blend 120, #/SD 9224 Said measuring-controlling means then resetting the now AVe- Mooney 93 45 55 Controller regulating the trialkylaluminum addition. In

this latter system the eiective catalyst level to the re- EXAMPLE IV y actor is independent of fluctuations in poison levels in Additional `runs are made to illustrate the aspect of the the reactor feed stream and is controlled Primarily by the invention depicted in FIGURE 4 wherein the Mooney of Mooney Viscosity of the Product rubberthe polymer is controlled Within a narrow range by blend- What I claim SI ing in either high or loW Mooney polymer as needed- 1. A process for the determination and control of the The stream 73 is diverted as described in Example II. Mooney Viscosity of. a rubbery Polymer comprising, meas- The stream passing through line 93 contains polymer turing the Weight Percent of Polymer (solids) in a solution having a Mooney of 49. A rango of 4512 isoosirod. A 0f Polymer and producing a first Signal representative portion of stream is diverted through the means for lheleOf, measuring the SOlUlOIl VSCOSlty Of Said SOllltlOl'l measuring tho solution viscosity rand refractive index of and producing e Second Sign-a1 representative thereof, comthe diverted stream. The information is transmitted to Puting the Mooney VSCOSity Of Said solution from said computer 132 wherein asignal proportional to the Mooney iirst and second signals and Producing a control Signal is transmitted to controller 133. valves 116 and 119 are representative thereof, and automatically adjusting e PIOG- normauy 1Osed- Logic system 134 receives a Signal from 70 ess variable responsive to said control signal to obtain a controller 133 and decides, on the basis of predetermined rubbery Polymer of the desired Mooney Viscosity values fed to it, to open valve 119. Valve 119 remains 2 Process for the Production of a rubbery Polymer open until the Mooney again reaches 46.9 at which time it comprising PolymeriZing a conjugated diene in a reacis closed or periodically adjusted to maintain the Mooney tion zone in the presence of an initiator, recovering an ofthe blend in line 93 at 451-2. 75 eluent from said zone comprising unreacted diene and polymer, measuring the refractive index of said efiluent and producing a first signal representative thereof, measuring the solution viscosity of said solution and producing a second signal representative thereof, computing the Mooney viscosity of said effluent from said first and said second signals and producing a control signal representative thereof, and automatically adjusting a process variable responsive to said control signal to obtain a rubbery polymer stream of the desired Mooney viscosity.

3. The process of claim 2 wherein said process variable comprises a concentration of initiator within said reaction zone.

4. The process of claim 2 wherein said process variable comprises the diversion of efuent having a Mooney viscosity outside a predetermined range from the polymer product stream.

5. A process for the production of rubbery polymer comprising contacting a conjugated diene in the presence of a liquid diluent in la reaction zone under polymerization conditions with an initiator comprising (A) an organometal having the formula RnM, wherein M is a metal selected from the group consisting of aluminum, gallium,

indium, beryllium, mercury, zinc Iand cadmium, R is a member selected from the group consisting of alkyl, cycloalkyl, aryl, analkyl and alkaryl radicals containing from 1 to 20 carbon atoms per molecule and n is equal to the valence of M, and (B) a member selected from the group consisting of (l) titanium tetraiodide, (2) mixtures of titanium tetrachloride and titanium tetraiodide and (3) iodine and ra titanium halide having the yformula TiX4, wherein X is selected from the group consisting of chlorine and bromine, recovering from said reaction zone an efiuent stream, adjusting the concentration of said effluent stream and removing at least .a portion of the unreacted conjugated diene, recovering a polymer product stream, continuously diverting a portion of said product stream to be measured, measuring the refractive index of said portion and producing a 4signal representative thereof, measuring lthe solution viscosity of said stream and producing a second signal representative thereof, computing the Mooney viscosity from said first and second signals, and producing a con'trol signal representative thereof, said signal actuating Ia logic system to control a process variable in response to changes in said control signal whereby the desired Mooney viscosity of the polymer stream is obtained.

6. The process of claim S wherein said process variable is the amount of initiator introduced into said reaction zone.

7. The process of claim 5 wherein said Mooney viscosity is determined `from the following relationship:

ML :logro M'l 789.3-526.S(R)

1.484-0.9798(RI) wherein ML=Mooney viscosity Rl=refractive index ,u.=solution viscosity, poise.

8. A process for the production of polybutadiene comprising introducing toluene, 1,3-butadiene and an initiator comprising triisobutylaluminum, titanium tetrachloride and iodine into a polymerization zone maintained at polymerization conditions, recovering from said reaction zone an effluent stream comprising unreacted butadiene and a solution of polybutadiene and toluene, removing at least a portion of said unreacted butadiene from said efuent stream by ashing, adjusting the concentration of said effluent stream to the range of 5 to 15 weight percent` polymer, recovering a product stream comprising polybutadiene solution from said ash zone, continuously diverting a portion of said product stream to be measured, measuring refractive Yindex of said diverted stream, and producing a first signal representative thereof, measuring the solution viscosity and producing a second signal representative thereof, computing the Mooney viscosity from said first and second signals and producing a control signal representative thereof, said signal actuating a logic system to control the amount of initiator introduced to said reaction zone in response to the computed Mooney viscosity -whereby the Mooneyv viscosity of said polymer stream is maintained within the range of 40-50.

.9. A process for the production of rubbery polymer comprising contacting a conjugated diene in the presence of a liquid diluent in the reaction zone under polymerization conditions with an initiator comprising (A) an organometal having the formula RnM, wherein M is a metal selected from the group consisting of aluminum, gallium, indium, beryllium, mercury, zinc and cadmium, R is -a member selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl radicals containing from .1 to 20 :carbon atoms per molecule and is equal to the valence of M, and (B) a member selected from the group consisting of (l) titanium tetraiodide, (2) mixtures of titanium tetrachloride and titanium tetraiodide and (3) iodine and a titanium halide having the formula TiX4, wherein X is selected from the group consisting of chlorine and bromine, recovering from said reaction zone an eiuent stream, adjusting the concentration of said effluent stream and removing at least a portion of the unreacted conjugated diene, recovering a polymer product stream, continuously diverting a portion of said product stream to be measured, measuring the refractive index of said diverted stream yand producing a signal representative thereof, measuring the solution viscosity of the stream and producing a second signal representative thereof, computing the Mooney viscosity of the sample product stream from said first and second signals and producing a control signal corresponding to the computed Mooney viscosity, said signal actuating a logic system to divert from said productstream portions of polymer outside a desired Mooney viscosity range in response to the computed Mooney viscosity whereby the vMooney viscosity of said product stream is maintained substantially constant.

10. A process for the production of polybutadiene cornprising introducing toluene, 1,3-bu-tadiene and an initiator comprising triisobutyl-aluminum, titanium tetrachloride and iodine into a polymerization zone maintained at polymerization conditions, recovering from said reaction zone an effluent stream comprising unreacted butadiene and a solution of polybutadiene and toluene, removing at least a portion of unreacted butadiene from said effluent stream by flashing, adjusting the concentration of said effluent stream to the range of 5 to 15 weight percent polymer, recovering a product stream comprising polybutadiene solution from said flash zone, continuously diverting a portion of said product stream to be measured, measuring the refractive index of said diverted stream, and producing a signal representative thereof of instruments producing a signal proportional to the values, measuring the solution viscosity of the ystream and producing a second signal representative thereof, computing the Mooney viscosity of the sample product stream and producing a control signal representative thereof, said control signal actuating a logic system which diver-ts from said product stream portions of polybutadiene outside of the predetermined Mooney viscosity range in response to the computed Mooney viscosity whereby the Mooney viscosity of said polybutadiene stream is maintained substantially constant. l

1 1. A process for the production of rubbery polymer comprising contacting a conjugated diene in the presence of a liquid diluent in the reaction zone under polymerization -conditions with an initiator comprising (A) an organometal having the formula RnM, wherein Mis a metal selected from the group consisting of aluminum, gallium, indium,- -beryllium, mercury, zinc and cadmium, R is 4a member selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and -alkaryl radicals containing from 1 to 20 carbon atoms per molecule and n is equal to the valence of M. and (B) a member selected `from the group consisting of (1,) titanium tetraiodide, (2) mixtures of titanium tetrachloride and titanium tetraiodide and (3)' iodine and a titanium halide having the formula TiX4 wherein X is selected from the group consisting of chlorine and b'romine, recovering from said reaction zone an eiiiuent stream, adjusting the concentration of said efuent stream and removing at least a portion of the unreacted conjugated diene, recovering a polymer product stream, continuously diverting a portion of said product stream to be measured, measuring the refractive index of said diverted stream and producing a signal representative thereof, measuring `the solution viscosity of the stream and producing a second signal representative thereof, computing the Mooney viscosity of the sample product stream from said first and second signals and producing a control signal corresponding to the computed Mooney viscosity, diverting polymer outside of a predetermined Mooney viscosity range value from said product stream in response to said'control signal, at least one portion of said polymer 'being above and at least one portion of said polymer being below said predetermined Mooney viscosity range, recombining these portions into the product stream in response to said computed Mooney viscosity in a ratio sufficient to maintain the Mooney viscosity of said product stream in a second desired Mooney viscosity range having narrower limits than said tirst desired Mooney viscosity range.

12. A process for the production of polybutadiene comprising introducing toluene, 1,3-butadiene and an initiator comprising triisobutylaluminum, titanium tetrachloride and iodine into a polymerization zone maintained at polymerization conditions, recovering from ysaid reaction zone an etiiuent stream comprising unreacted butadiene and a solution of i polybutadiene and toluene, removing at least a portion of unreacted butadiene from said etiiuent stream by ashing, adjusting the concentration of said efuent stream to the range of 5 to ilS weight percent polymer, recovering a product stream comprising polybutadiene solution from said ash zone, continuously diverting a portion of said product stream to be measured, measuring the refractive index of said diverted stream and producing a signal representative thereof, measuring the solution viscosity of the stream and producing a second signal representative thereof, computing the Mooney Viscosity of the sample product stream fromsaid `first and second signals and producing a control signal corresponding tothe computed Mooney viscosity, and diverting polybutadiene outside the Mooney range of 40 to 50 from said product stream in response to said control signal, at least one portion being above and at least one portion being below said Mooney viscosity range, recombining these portions into the product stream in response to said vcomputed -Mooney viscosity so as to maintain said Mooney viscosity of said final product stream in a range of 43-45.

13. In apparatus for producing a rubbery polymer comprising in combination a reactor, inlet conduits for introducing conjugated diene and catalyst into said reactor and an outlet conduit for removing la product stream from said reactor, the improvement comprising a withdrawal conduit for continuously withdrawing a portion of said product stream, means for producing a signal proportional to the solution viscosity of said withdrawn portion, means for producing a second signal proportional to the weight percent polymer of said withdrawn portion, and computing means operatively connected to said means for measuring solution viscosity and weight percent polymer receiving said signals and producing a signal proportional to the combination of said solution viscosity and weight percent polymer of said Withdrawn portion.

14. Apparatus for producing a rubbery polymer oom- Pl-SDg in combination a reactor, a rst inlet conduit for introducing a conjugated diene into said reactor, a second inlet conduit for introducing an initiator which polymerizes said -conjugated diene into said reactor, means for maintaining said reactor at polymerization condi-tions, an 5 outlet conduit means for removing a product stream from said reactor, a third conduit means for continuously withdrawing a portion of said product stream, means for measuring the solution viscosity of said portion, means for measuring the Weight percent polymer of said portion, computing means for determining a value representative of the Mooney viscosity of said portion from said measurements, means for producing a signal proportional to said value, adjusting means for varying a process variable, controlling means operatively connected to said acljusting means and said signal producing means for adjusting said process variable in response to said signal so Vas to maintain the Mooney viscosity substantially constant. v 15. The apparatus of claim 14 wherein said adjusting means comprises valve means disposed in said second inlet conduit.

16. The apparatus of claim 14 wherein said adjusting means comprises valve means disposed in said outlet conduit for diverting polymer from said conduit which is outside a predetermined value range into a diversion conduit.

17. The apparatus of claim 16 wherein said outlet conduit contains a diversion conduit in open communication with said outlet conduit, a first valve means in said outlet conduit downstream from said diversion conduit, a first and second surge vessels for containing polymer in open communication with said diversion conduit, a second and third valve means disposed in said diversion conduit so as to regulate flow to said rst and second surge vessels respectively, a irst controlling means operatively connected to said computing means and said rst, second and third valves opening further at least one of said valves so as to distribute the polymer stream according to a predetermined first value range, said -rst vessel receiving polymer above the desired range and said second vessel receiving polymer below the desired range, a fourth conduit in communication with said -irst and second surge vessels and said outlet conduit downstreamifrom said first 45' valve, a fourth and fth valve means disposed in said fourth valves for regulating flow from said first and second vessels respectively, a second computing means for determining a second value representative of the Mooney viscosity of said polymer in said outlet conduit downstream from said fourth conduit, a second signal producing means for transmitting a signal proportional to said second value, a second controlling means operatively connected to said second signal producing means and said fourth and fifth valves opening at least one of said valves to permit flow of polymer through said fourth conduit in a quantity and at a value sufficient to further adjust the value of the polymer in said outlet conduit to a value within a second predetermined range narrower than said first predetermined range.

References Cited by the Examiner UNITED STATES PATENTS JOSEPH L. SCHOFER, Primary Examiner.

MORRIS LIEBERMAN, Examiner. 

5. A PROCESS FOR THE PRODUCTION OF RUBBERY POLYMER COMPRISING CONTACTING A CONJUGATED DIENE IN THE PRESENCE OF A LIQUID DILUENT IN A REACTION ZONE UNDER POLYMERIZATION CONDITIONS WITH AN INITIATOR COMPRISING (A) AN ORGANOMETAL HAVING THE FORMULA RNM, WHEREIN M IS A METAL SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, GALLIUM, INDIUM, BERYLLIUM, MERCURY, ZINC AND CADMIUM, R IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF ALKYL, CYCLOALKYL, ARYL, ARALKYL AND ALKARYL RADICALS CONTAINING FROM 1 TO 20 CARBON ATOMS PER MOLECULE AND N IS EQUAL TO THE VALENCE OF M, AND (B) A MEMBER SELECTED FROM THE GROUP CONSISTING OF (1) TITANIUM TETRAIODIDE, (2) MIXTURES OF TITANIUM TETRACHLORIDE AND TITANIUM TETRAIODIDE AND (3) IODINE AND A TINANIUM HALIDE HAVING THE FORMULA TIX4, WHEREIN X IS SELECTED FROM THE GROUP CONSISTING OF CHLORINE AND BROMINE, RECOVERING FROM SAID REACTION ZONE AN EFFLUENT STREAM, ADJUSTING THE CONCENTRATION OF SAID EFFLUENT STREAM AND REMOVING AT LEAST A PORTION OF THE UNREACTED CONJUGATED DIENE, RECOVERING A POLYMER PRODUCT STREAM, CONTINUOUSLY DIVERTING A PORTION OF SAID PRODUCT STREAM TO BE MEASURED, MEASURING THE REFRACTIVE INDEX OF SAID PORTION AND PRODUCING A SIGNAL REPRESENTATIVE THEREOF, MEASURING THE SOLUTION VISCOSITY OF SAID STREAM AND PRODUCING A SECOND SIGNAL REPRESENTATIVE THEREOF, COMPUTING THE MOONEY VISCOSITY FROM SAID FIRST AND SECOND SIGNALS, AND PRODUCING A CONTROL SIGNAL REPRESENTATIVE THEREOF, SAID SIGNAL ACTUATING A LOGIC SYSTEM TO CONTROL A PROCESS VARIABLE IN RESPONSE TO CHANGES IN SAID CONTROL SIGNAL WHEREBY THE DESIRED MOONEY VISCOSITY OF THE POLYMER STREAM IS OBTAINED. 